.course-lesson-nav {
  border-right: 1px solid #e6e6e6;
  width: 300px;
  transition: width 0.3s ease;
  position: relative;
}

.course-lesson-nav.collapsed {
  width: 10px;
}

.collapse-toggle {
  position: absolute;
  top: 10px;
  right: -20px;
  z-index: 100;
  cursor: pointer;
  padding: 5px;
  border-radius: 50%;
  background-color: #f0f0f0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
}

.collapse-toggle:hover {
  background-color: #e0e0e0;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.course-lesson-menu {
  border: none;
  background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
  border-radius: 10px;
  margin: 10px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.lesson-item {
  padding-left: 20px !important;
  border-radius: 8px;
  margin: 0px 10px;
  transition: all 0.3s ease;
  font-family: 'DynaPuff light', 'fangsong';
  line-height: 2rem !important;
  height: 2rem !important;
}

.lesson-item:hover {
  background-color: #e9ecef !important;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.lesson-item .el-tag {
  margin-left: 10px;
  border-radius: 4px;
}

.course-link {
  margin-left: auto;
  font-size: 12px;
  padding: 4px 8px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  border: none;
  background-color: #409eff;
  color: darkgray !important;
  font-weight: 500;
}

.course-link:hover {
  background-color: #337ecc !important;
  box-shadow: 0 4px 12px rgba(64, 158, 255, 0.3);
  transform: translateY(-2px);
  color: white !important;
}

@media (max-width: 768px) {
  .course-lesson-nav {
    display: none;
  }
}

.rotate-icon{
  animation: rotateIcon 1s infinite linear;
}
@keyframes rotateIcon {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}